Hardware characterization is a very costly and time consuming effort which involves many resources, multiple test pattern generation and expensive tester time. Designs using several power supplies usually require special care during testing and hardware characterization. Reducing testing time on the one hand and simplifying test patterns on the other hand are key for chip testing.
During testing of a circuit design, stress testing may be performed. In some cases, the stress test includes performing voltage testing by connecting the circuit to two different power supplies. As a result, the circuit may be tested under different conditions, including different voltages. Different voltages may cause excessive current flows, Bias Temperature Instability (BTI) shifts, and even breaking of the circuit if too extreme.